Research Topic: 110,000 Ugandan HIV children and 1 million non-infected AIDS orphans will have poor or inconsistent caregiving because one or both parents are ill or dead from AIDS (UNAIDS 2006). Consequently, the cognitive and social development of these children may be stunted in early childhood, and eventually they will perform more poorly in school. Mediational intervention for sensitizing caregivers (MISC) has a structured curriculum and training program to teach HIV mothers/caregivers the skills for enhancing their child's cognitive and social development in the home each day. This is done by teaching mothers/caregivers how to focus a child's attention, excite a child's interest, expand her cognitive awareness, encourage her sense of competence, and regulate behavior during play, feeding, bathing and working. To adapt MISC to the Ugandan context and demonstrate its effectiveness for enhancing the cognitive and social development of HIV children and orphans, we will use a four-part protocol for evaluating parent training programs: context evaluation, input evaluation, process evaluation, and product evaluation (CIPP Model of Evaluation). Study Aim 1 is the context evaluation of MISC through the use of focus groups of local community leaders, teachers, and caregivers, partnering with us to adapt MISC to the Ugandan context. Study Aim 2 involves the input evaluation of appropriateness and acceptability of MISC training for the caregivers and household through interviews and training compliance. Study Aim 3 is the process evaluation of the fidelity of intervention though home observation and evaluation of HOME quality, and videotape evaluation of caregiving interactions between mother/caregiver and child, as well as changes in the caregivers own attitudes and approach throughout the year-long training period. Study Aim 4 evaluates the product or benefit of the MISC training;in terms of the child's gains on the Mullen Scales of Early Learning, the Early Childhood Vigilance Test (ECVT) of attention, the Color-Object Association Test (COAT) for memory, and the Child Behavior Checklist (CBCL) for psychosocial adjustment. Mothers/caregivers of half of 120 HIV-infected and 120 non-infected preschool AIDS orphans in Kayunga District, Uganda, will be assigned to monthly home-based MISC training for one year. The remaining children and caregivers will continue to receive the regular monthly home health care visits. MISC for both the HIV infected and non-infected orphans will lead to greater gains on the Mullen learning, ECVT attention, and COAT memory scores compared to non- intervention children. These gains will be mediated by improved scores on monthly videotaped caregiving samples evaluated for MISC features, HOME scale quality of home environment, and child/caregiver quality interactions (CCQI) scores from home-based observations. These gains will be moderated by clinical stability of the HIV children. Establishing the feasibility and effectiveness of MISC caregiving training will provide a strategic and sustainable means of cognitive enhancement for millions of HIV-affected children in resource-poor settings. Beyond the direct neurodevelopmental impact of pediatric HIV infection, the public health burden of HIV disease for tens of millions of HIV orphans globally is monumental when considering how it further compromises quality of home environment and caregiving for children already impoverished. In the African context, home-based caregiver training interventions to enhance the developmental milieu of HIV-affected children may be the single most developmentally strategic, culturally relevant, and resource sustainable means of buffering them from this impact of HIV disease. More broadly, caregiver training interventions may also enhance the cognitive ability and psychosocial adjustment of all children at risk from poverty and other public health challenges to the second of the UN Millennium Development Goals, which is to ensure that all children are able to complete primary schooling1.